Sat Oct 07, 2017 10:40 pm by Monsonmotors
Next time drive it without the air cleaner on it and after you shut it off look down the carb with a strong flashlight.
It may take a minute or two to see what you need to see.
If you see fuel rolling out of the main discharge nozzle hot with the engine off you can have more than one possible problem:
1) Sure the carb can be malfunctioning/ flooding. It may need to be rebuilt.
2) A common problem with unpressurized gasoline (unpressurized carbs vs. pressurized fuel injection) is that too much intake manifold heat can cause fuel to boil.
3) you can make or buy a phenolic spacer to place in between the carb base and the intake manifold.
Many, many carbureted vehicles came from the factory with a carb phenolic spacer installed. No unproven technology, here. This spacer slows down heat transfer from the intake manifold.
4) it's also possible that the engine is running too hot, causing fuel to boil in the carb or that the heat riser is stuck in the hot position. Can't blame the carb for that.
5) these carbs run on relatively low fuel pressure. It's possible that the fuel pump is developing more pressure than the carb can handle. Most American stuff I've worked on the fuel pressure should be like 3-6 psi.
6) the same way the carb can be insulated from heat via a phenolic spacer so can the mechanical fuel pump, if used. Again, many carbureted vehicles came with a fuel pump phenolic spacer.
7) I've learned through hard experience that all other possibilities should be explored before immediately condemning an otherwise functioning carburetor.
8) best of luck!